Thermostat Housing Leak (Causes & Solutions)

Are you wondering why you have a thermostat housing leak? Are you equally wondering how this can be fixed and the cost?

If these are the questions on your mind, you’ve found the right article; this article answers all these questions and more.

This article will explain why you have a thermostat housing leak, the symptoms, and what may happen if the thermostat housing leaks. We will also explain The steps you need to take to fix a thermostat housing leak, so sit back and find out all you need to know.

The car possesses an integrated or stand-alone thermostat housing of the finest quality metal or plastic. Even though these components are devised to outlast the thermostat itself typically, and it should, your thermostat may end up springing a leak when exposed to excessive temperature.

Once the thermostat housing is damaged, warped, or cracked anyhow, the system will experience a coolant leakage. A worn or failed seal can also result in this.

When the thermostat housing continues leaking, it may cause the engine to overheat. Therefore it is advisable to fix the problem immediately after it occurs. Unfortunately, the housing is just one likely source of leakage. Coolant surge tanks can equally be leaking and may require a replacement.

Also, on modern cars that use hot coolant and even aluminum-and-plastic radiators, there are usually plastic fittings on these cars. However, parts carrying plastic coolants are more prone to leakages.

Also Read: Thermostat Housing (Functions, Symptoms & Replacement)

Signs of Thermostat Housing Leak

Normally, when you park your vehicle for some time, the temperature gauge should be reading low. As the car keeps moving, the temperature gauge gradually moves up until it reaches about the middle point in the gauge; this signals that the engine is performing optimally.

1. OBD Codes

When an engine moves a little above 200 degrees close to the middle of the temperature gauge, this indicates the engine is healthy. A cold running engine will generate either a P0128 or a P0125 code, which can result in the engine developing a sludge that can destroy the engine over time.

2. Thermostat Valve Stuck Closed

one may observe a very high-temperature reading if the thermostat’s valve is tightly closed. If you keep driving the car in this condition, the engine components risk getting damaged.

3. Thermostat Valve Stuck Open

This doesn’t happen often, but the thermostat valve will more likely open sooner than later or become defective. It will not take time for serious damage to be done. When the thermostat housing leaks, it causes the coolant to become low.

4. Low Coolant Warning Light

When the level of the coolant drops lower than normal due to the housing leakage, the low coolant alarm light may turn on. Also, when the engine is overheating, the check engine light will appear, or when the thermostat performance sends out, trouble codes will be logged. One may also observe that fluid is leaking under the car.

5. Inoperative Heater

The heater of the car depends on hot coolant. A low-level coolant caused by a thermostat housing leakage can lead to the inoperative heater of the car.

Fixing a Thermostat Housing Leak

A damaged or cracked thermostat housing or damaged seal in-between the engine and thermostat housing may cause coolant leakage. It will require you to replace the defective component in both instances. If you have no idea how to do this, it’s better to take the car to a mechanic so that he can determine the problem and exclude other issues with similar signs.

You should ensure that the thermostat plate is in the car’s recessed area if you want to replace the thermostat before tightening the housing. If the car thermostat uses a paper gasket that is placed vertically, then the situation is more critical.

Occasionally, the recessed area may be in the manifold where the thermostat is mounted, or it could be in the thermostat housing. Although a little dap of glue and the gasket should be used to fix the thermostat in the right place, excessive use of the glue should be avoided.

How Much Does a Thermostat Housing Replacement Cost?

To replace a thermostat housing, you can expect to pay between $50 – $250 for only parts. The cost of the labor will be around $130 to $170. Note that more related repairs may be needed, and you’ll end up spending more on them. Cast aluminum aftermarket units may be used to replace some of the plastic thermostat housings, which will outlast the original plastic and don’t cost more.

Also Read: Radiator Hose Replacement Cost

Can I Drive With a Thermostat Housing Leak?

A leak in the thermostat housing requires attention and must be addressed; replacing the thermostat housing is necessary as soon as possible. The car should be stopped and towed to a mechanic shop if this leak is big enough to cause the engine to run too hot.

In some instances, an electronic mechanism in the vehicle will cause the vehicle to shut down partially; this will prevent you from going long distances or driving fast by making the engine to be partially idle.

This will also help you take the car to a repair shop before you are stranded; the car can eventually shut down totally. Also, as an indication that the coolant is low, the low coolant warning light is normally shown on the car’s dashboard. This will occur before the engine starts to overheat. The above are the few methods of protecting the car against potential harm.

The thermostat housing should ideally last as long as the car itself, and typically, it ought to last more than the thermostat. However, a crack could result from constant heating and cooling with the rubber coolant hose shifting constantly.

If the vehicle’s engine is overheating, the thermostat housing needs to be checked for wear or damage. Your mechanic needs to do this also when replacing the car’s radiator hose.

Can I Replace the Thermostat Housing Myself?

To save money, you can choose to change the vehicle’s thermostat housing by yourself.

A significant amount of money can be saved if you have good experience working on cars and enough time to fix the problem by yourself because the average labor rate is about $200 for professionals.

To avoid damaging other components within the cooling system or risk injuring yourself, you should read this entire article before starting to fix the car so that you can know and follow all precautions.

How Do You Stop a Thermostat Housing Leak? (Quick Fix)

1. Replace or tighten the hose if the leakage is at the coolant hose.
2. Equally, if the leakage occurs at the flange gasket, the housing should be removed, all the gasket residual materials should be scraped off, and a new sealant should be applied with a new gasket. The good idea is to change the thermostat while you put the thermostat housing off.
3. The same thing above is to be done when faced with cracked housing but with a new thermostat housing.
4. Doing this used to be a job of 10 minutes, but these days a lot of peripheral equipment is needed for the housing to be removed on some newer vehicles.

How to Fix the Thermostat Housing Leak by Replacing the Thermostat Housing?

The process of changing a housing that is leaking is rather simple but can result in a bit of engine cooling problems. You should contemplate changing the housing immediately you observe water gathering beneath the car, or you have to constantly top off the coolant to prevent further damage to the parts.

Step-by-step guide on how to replace your car thermostat housing

1. Prepare Your Working Area

You should park and apply the handbrake to your vehicle on a flat surface before trying to change the vehicle’s thermostat housing. After that, the bolts holding down the vehicle’s engine covers should be loosened up and taken out from their various positions.

2. Allow the Engine to Cool Down

At this point, before proceeding, ensure the engine cools down enough. To ensure everything has cooled off, wait for less than one hour while the car sits. There is a possibility of making the cylinder head crack if the engine is overheating during this very process, which may necessitate the replacement of the full engine.

3. Detach the Coolant Reservoir

The vehicle’s reservoir coolant tank should be disassembled by cutting off all its lines. Next, deplete any remaining coolant into a neat receptacle after removing all the bolts that keep the radiator in its position. Some baking soda and water should be added to the radiator if you don’t want to delete all the remaining coolants. This will prevent the possibility of future corrosion by neutralizing the leftover acid.

4. Loosen the Thermostat Housing Bolts

Two bolts hold the housing in its position; you should locate and remove them using a socket wrench. It is advised that you get an adjustable crescent wrench to help you do this if you have no experience working on a car before. These wrenches can be helpful in about anything as they are very versatile. Using the adjustable crescent wrench permits you to put pressure on various spots without removing your hands from it; this is why it is the preferred choice.

5. Detach Thermostat Housing From the Engine

The old thermostat housing should effortlessly be removed after the bolts fastening it to its position have been removed by pulling it straight up. After that, you should examine the gasket at the point the housing links up with the cylinder head and coolant hoses; it is advised that you consider replacing the gasket if they look worn or damaged.

6. Clean the Surface Where Your New Housing Will Go

Before the new housing is attached, the area where the new housing will be placed should be cleaned with no dirt particles or debris resting on the metal part. This is to make sure that it is properly sealed and avoid future leakages if you didn’t do this before now.

In addition, a good engine degreaser should be used to clean out the old gasket residue if found leaking somewhere else apart from the previous housing.

If this is not done, leakages may occur in another part within the cooling system and cause other parts like the radiator to overheat or get damaged.

7. Place the New Housing in Place

The new housing should be placed in its position, and the bolts tightened to make sure it stays in its place firmly. The coolant reservoir should be filled while the car is starting after all the components have been attached to ensure everything is permitted to circulate properly through the car’s engine.

You should stop the vehicle and check what’s wrong immediately after you observe air bubbles or a leak coming out from the car’s coolant reservoir when the car is in the process of starting up. This may indicate a defective gasket that was not properly placed during installation.

Also Read: Blue Light on Dashboard (Everything to Know)

Frequently Asked Questions – Thermostat Housing Leak

Conclusion – Thermostat Housing Leak

The factors which cause thermostat housing leaks can be caused by cracked or damaged housing, a damaged seal, or exposure to extreme temperatures and movement in the rubber coolant hose.

We hope this post was of help to you. Please feel free to check out our other blog articles if you want to get more tips for preventing car troubles!